Method, device and system for responsive load management using frequency regulation credits

ABSTRACT

A method, device and system for responsive load management using frequency regulation credits. The method includes using an AC frequency measuring device, measuring a current AC frequency on an AC power line; using a power consumption measuring device, measuring a current power consumption on the AC power line over a period of time equal to a sampling interval; calculating a power consumption moving average of a last N power current power consumptions measured, where N is a positive integer greater than 1; generating credits or debits based on the current power consumption, the current AC frequency and the power consumption moving average; adding the credits or debits to a frequency regulation credit; and for each next sampling interval repeating measuring the current AC frequency, measuring current power consumption, calculating the power consumption moving average, generating the credits or debits, and adding the credits or debits to the frequency regulation credit.

RELATED APPLICATIONS

This Application is a continuation of U.S. patent application Ser. No.12/263,732 filed on Nov. 23, 2009.

FIELD OF THE INVENTION

The present invention relates to the field of AC power grid loadmanagement; more specifically, it relates to a method and device forfrequency responsive load management using frequency regulation credits.

BACKGROUND

Currently, electric power providers must constantly add and remove powergeneration capacity to match real-time demand. This power supply/demandbalancing requires bringing on and off line auxiliary generatingfacilities. This process not only increases the costs of generatingpower, but provides little incentive for power conservation.Accordingly, there exists a need in the art to mitigate the deficienciesand limitations described herein above.

SUMMARY

A first aspect of the present invention is a method, comprising: usingan AC frequency measuring device, measuring a current AC frequency on anAC power line; using a power consumption measuring device, measuring acurrent power consumption on the AC power line over a period of timeequal to a sampling interval; calculating a power consumption movingaverage of a last N power current power consumptions measured, where Nis a positive integer greater than 1; generating credits or debits basedon the current power consumption, the current AC frequency and the powerconsumption moving average; adding the credits or debits to a frequencyregulation credit; and for each next sampling interval repeating themeasuring the current AC frequency, the measuring the current powerconsumption, the calculating the power consumption moving average, thegenerating the credits or debits, and the adding the credits or debitsto the frequency regulation credit.

A second aspect of the present invention is a device, comprising: an ACfrequency measuring device; an AC power measuring device; means forgenerating a frequency regulation credit based on signals from the ACfrequency measuring device and the AC power measuring device, the meansfor generating the frequency regulation credit connected to the ACfrequency measuring device and to the AC power measuring device; andmeans for displaying, recording or both displaying and recording thefrequency regulation credit.

A third aspect of the present invention is a computer system comprisinga processor, an address/data bus coupled to the processor, and acomputer-readable memory unit coupled to communicate with the processor,the memory unit containing instructions that when executed by theprocessor implement a method for frequency responsive load managementusing frequency regulation credits, the method comprising the computerimplemented steps of: receiving from an AC frequency measuring device, acurrent AC frequency on an AC power line; receiving from a powerconsumption measuring device, a current power consumption on the ACpower line over a period of time equal to a sampling interval;calculating a power consumption moving average of a last N power currentpower consumptions measured, where N is a positive integer greater than1; generating credits or debits based on the current power consumption,the current AC frequency and the power consumption moving average;adding the credits or debits to a frequency regulation credit, storingthe frequency regulation credit on the memory unit; and for each nextsampling interval repeating the steps of receiving from the AC frequencymeasuring device the current AC frequency on an AC power line, receivingfrom the power consumption measuring device the current powerconsumption, calculating the power consumption moving average,generating the credits or debits adding the credits or debits to thefrequency regulation credit, and storing the frequency regulation crediton the memory unit.

These and other aspects of the invention are described below.

BRIEF DESCRIPTION OF THE DRAWINGS

The features of the invention are set forth in the appended claims. Theinvention itself, however, will be best understood by reference to thefollowing detailed description of an illustrative embodiment when readin conjunction with the accompanying drawings, wherein:

FIG. 1 a diagram illustrating an exemplary customer facility linked to apower grid according to an embodiment of the present invention;

FIG. 2 is a diagram of illustrating the major components of a linemonitoring device according to embodiments of the present invention;

FIG. 3 is an exemplary plot of AC line frequency versus time measured bya line monitoring device according to an embodiment of the presentinvention;

FIG. 4 is an exemplary plot of power consumption versus time measured bya load management device according to an embodiment of the presentinvention;

FIG. 5 is an exemplary plot of a moving running average power consumedversus time according to an embodiment of the present invention;

FIG. 6 is a flowchart of a method of frequency responsive loadmanagement according to an embodiment of the present invention;

FIG. 7 is block diagram of an exemplary line monitoring deviceimplemented as a power and frequency regulation meter according to anembodiment of the present invention;

FIG. 8 is block diagram of the power line interface of FIG. 7;

FIG. 9 is a mechanical drawing of an exemplary power meter according toan embodiment of the present invention; and

FIG. 10 is block diagram of a general-purpose computer.

DETAILED DESCRIPTION

The direction of alternating electric current (AC) periodically changesand results in a sinusoidal change of voltage from a maximum positivevalue to a minimum negative value over time. Thus, the frequency of ACpower can be defined on a plot of voltage versus angular frequency thenumber of angular frequency cycles (0 to 360 degrees) per unit of timeand the usual unit of measurement is Hertz, also commonly cycles/second,often shorted to cycles. AC power grids are designed to run mostefficiently at a nominal frequency. In one example, the nominalfrequency of an AC power grid is 60 Hz. In one example, the nominalfrequency of an AC power grid is 50 Hz. The AC power grids of interestin the present invention are those bulk electrical transfer networks andsub-networks for transferring electricity from commercial powergenerating stations to consumers, such as households, businesses andfactories. In one example, an AC power grid comprises a main powerplant, an optional auxiliary power plant, and transmission lines.

As power demand (e.g., power consumption or load) increases on an ACpower grid, the frequency decreases. In order to increase the frequency,either an increase in power generation or decrease in demand isrequired. Power generation can be increased by running main plants athigher output or bringing auxiliary power plants on line. Increasing theoutput of main power plants increases the maintenance costs anddecreases the life of the plant, resulting in increased costs. Bringingauxiliary power plants online increase costs because auxiliary powerplants often use fuels that are more expensive and/or are less efficientand thus more costly per unit of energy generated. As power demanddecreases on an AC power grid, the frequency increases. In order todecrease the frequency, either a decrease in power generation orincrease in demand is required. The methods and systems of the presentinvention monitor a customer's usage of power as the AC line frequencyon a power grid supplying power to the consumer changes. The customer ispenalized for using more power during a period of low AC line frequencyor for using less power during a period of high AC line frequency gridthus providing incentive for the consumer to assist in maintaining theAC line frequency of the power grid at or close to nominal. Thus thecustomer is rewarded for increasing stability in the AC line frequencyand penalized for deceasing stability in the AC line frequency. Therewards are in the form of frequency regulation credits and frequencyregulation debits that, in one example, will increase (if frequencyregulation debits exceed frequency regulation credits) or decrease (iffrequency regulation credits exceed frequency regulation debits) acustomer's bill. In another example, the frequency regulation debits andfrequency regulation credits may be used to adjust a customer's electricrate (e.g., cost per KW/hour).

FIG. 1 a diagram illustrating an exemplary customer facility linked to apower grid according to an embodiment of the present invention. In FIG.1, a customer facility 100 is connected to an AC power grid 105 by apower line 110. Customer facility 100 includes a line monitoring device115, and two exemplary loads 120A and 120B. AC power passes through loadmonitoring device to loads 120A and 120B through wires 125A and 125Brespectively. Examples of customer facilities include privateresidences, commercial and industrial facilities. Loads may be directconnections to equipment that use AC power or to a distribution device(e.g., a circuit breaker box or a load center). While two loads areillustrated in FIG. 1, there may be as few as one load or more than twoloads.

FIG. 2 is a diagram illustrating the major components of a linemonitoring device according to embodiments of the present invention. InFIG. 2, line monitoring device 115A includes a frequency meter 130,watt-hour meters 135A and 135B, a calculation unit 140, an optionalhuman interface 145 an optional telephone connection (e.g., modem) 150A,an optional cable (i.e., non-telephone communications) modem 150B, anoptional Internet connection 155 which may be wired or wireless and anoptional private wireless communication device (e.g., wireless modem)160. Power from an AC power grid passes along wire 110A through wattmeters 135A and 135B to respective loads A and B. Watt meters 135A and135B measure the amount of power (e.g., watt-hours) being consumed andpasses that information to calculation unit 140. Frequency meter 130measures the AC line frequency (e.g. Hz or cycles/second) on wire 110Aand passes that information to calculation unit 140. The power andfrequency measurements may be passed to calculation unit 140 as analogor digital signals. If digital, the information is in the form of aperiodic sample.

Calculation unit 140 calculates debits and credits as described infrawith respect to FIGS. 3, 4 and 5 and the method described by FIG. 6.Interface 145 may display the frequency regulation credit accumulated(the sum of credits and debits as described infra) and the KW(kilowatt)-hours used. The frequency regulation credit may be positive,negative or zero. The frequency regulation credit and the KW-hours usedmay be transmitted to the power generation facility modems 150A, 150B or155 for billing and/or record keeping purposes. Wireless modem 155 maybe a short range device accessible by a portable reading device.Interface 145 may take the form of a data port into which a recordingdevice may be plugged in order to download the frequency regulationcredits/frequency regulation debits accumulated (or the sum of frequencyregulation credits and frequency regulation debits) and the KW-hoursused by a human meter reader. Frequency meter 130 and watt-hour meters135A and 135B may include digital or analog displays of the AC linefrequency and KW-hours respectively. The KW-hours displayed may show thecurrent rate of power usage, total power used or both the current rateof power usage and total power used.

FIGS. 3, 4 and 5 are an aid in understanding how the frequencyregulation credit is calculated. The overall time period and scale ofthe time axis depicted in each of FIGS. 3, 4, and 5 is the same. Theoverall time period is divided into five distinct time ranges A, B, C, Dand E. For the purposes of an example frequency regulation creditcalculation, in FIGS. 3, 4 and 5, the sampling interval (SI) is1/second, but in general is configurable and may be set as required.

FIG. 3 is an exemplary plot of AC line frequency versus time measured bya line monitoring device according to an embodiment of the presentinvention. In FIG. 3, a curve 160 represents AC line frequency in Hz onthe incoming power line versus time in seconds. Line 170 indicates thenominal frequency of the power grid (e.g., 60.00 Hz). Line 175A is anupper threshold frequency (for example set a 60.02 Hz) and line 175B isa lower threshold frequency (for example set a 59.98 Hz). The upperthreshold frequency is always more positive than the nominal frequencyand the nominal frequency is always more positive than the lowerthreshold frequency. Debits and credits are calculated only for thosetime periods when the measured AC line frequency is greater than orequal to the upper threshold frequency or less than or equal to thelower threshold frequency. At a time T1 the frequency has a measuredvalue of F1 Hz. At time T2, the frequency has a measured value of F2 Hz.At a time T3 the frequency has a measured value of F3 Hz. At a time T4the frequency has a measured value of F4 Hz.

In time range A, the measured frequency is between the upper and lowerthreshold frequencies so no debits or credits will result. In time rangeB, the measured frequency is below the lower threshold frequency sodebits or credits may result. Note, both debits and credits can begenerated when the measured frequency is below the lower thresholdfrequency depending upon the customer's power usage before and duringtime period B. In time range C, the measured frequency is again betweenthe upper and lower threshold frequencies no debits or credits willresult. In time range D, the measured frequency is above the upperthreshold frequency so debits and credits may result. Note, both debitsand credits can be generated when the measured frequency is above theupper threshold frequency depending upon the customer's power usagebefore and during time period D. In time range E, the measured frequencyis once again within the upper and lower threshold frequencies so debitsand credits will not result.

In FIG. 4, a curve 180 is an exemplary plot of power consumption inwatt-hours versus time in seconds. Each point on curve 180 is the amountof power consumed in a sampling interval of c second (i.e., the integralof dP/dt from 0 to c where P is watts and t is time in seconds). In thepresent example c is equal to one second. At a time T1 the powerconsumed has a measured value of P1 Hz. At time T2, the power consumedhas a measured value of P2 Hz. At a time T3 the power consumed has ameasured value of P3 Hz. At a time T4 the power consumed has a measuredvalue of P4 Hz.

In FIG. 5, a curve 185 is an exemplary plot of the moving average ofpower consumption in watt-hours for a given sampling period versus timein seconds. Continuing the present example, a moving average powerconsumption period (MAVP) is set to 15 minutes though in general it isconfigurable and may set as required. Thus, each moving average datapoint is the average of the last 900 (15 minutes×60 seconds/minute×1sample/second) power consumption points of FIG. 4. At a time T1 themoving average of power consumed has a measured value of M1 Hz. At timeT2, the moving average of power consumed has a measured value of M2 Hz.At a time T3 the moving average of power consumed has a measured valueof M3 Hz. At a time T4 the moving average of power consumed has ameasured value of M4 Hz.

In the following discussion, it should be kept in mind that increasingload decreases AC line frequency and decreasing load, increases AC linefrequency. At time T1, AC line frequency is below the lower frequencylimit (see FIG. 3). The power consumed at T1 (see FIG. 4) is less thanthe moving average power at T1 (see FIG. 5) so power consumption isdecreasing. A credit will result because customer power usage whencompared to the power consumption moving average is driving the AC linefrequency toward nominal. At time T2, AC line frequency is below thelower frequency limit (see FIG. 3). The power consumed at T2 (see FIG.4) is greater than the moving average power at T2 (see FIG. 5) so powerconsumption is increasing. A debit will result because customer powerusage when compared to the power consumption moving average is drivingthe AC line frequency away from nominal. At time T3, AC line frequencyis above the upper frequency limit (see FIG. 3). The power consumed atT3 (see FIG. 4) is greater than the moving average power at T3 (see FIG.5) so power consumption is increasing. A credit will result becausecustomer power usage when compared to the power consumption movingaverage is driving the AC line frequency toward nominal. At time T4, ACline frequency is above the upper frequency limit (see FIG. 3). Thepower consumed at T3 (see FIG. 4) is less than the moving average powerat T3 (see FIG. 5) so power consumption is decreasing. A debit willresult because customer power usage when compared to the powerconsumption moving average is driving the AC line frequency away fromnominal.

Assuming credits are positive and debits are negative the followingformula will result in a the proper sign of a frequency regulationcredit when summed for all sample intervals:

FRC=SF Σ[(P−M)(MF)]  (1)

where:

-   FRC is the frequency regulation credit;-   P is the power consumed in a sampling interval;-   M is the moving average of power consumed over N sampling intervals    where N is a whole positive integer equal to or greater than 2 (the    power consumption moving average);-   MF is a multiplier function; and-   SF is an optional scaling factor so the FRC is not an unreasonably    large or small number in terms of output or display.

In its simplest implementation MF is one (1) when the AC line frequencyis less than or equal to the lower the lower threshold frequency, one(1) when the AC line frequency is equal to or greater then the upperthreshold frequency, and zero (0) when the AC line frequency is betweenthe lower and upper threshold frequencies. The term (P−M) results in thein the proper signage for FRC (negative for debits, positive forcredits). MF may be adjusted to reward or penalize the consumer morewhen the frequency is low than when the frequency is high. For example,MF is five (5) when the AC line frequency is less than or equal to thelower the lower threshold frequency, one (1) when the AC line frequencyis equal to or greater then the upper threshold frequency, and zero (0)when the AC line frequency is between the lower and upper thresholdfrequencies.

MF may be adjusted to provide a sliding scale that increases theabsolute value of credits and debits the further away from nominal themeasured frequency is. This is illustrated in Table I where 60.00 Hz isthe nominal frequency, 60.02 is the upper threshold frequency and 59.98is the lower threshold frequency. Two options are shown, the first (MF1)provides the same MP for the same absolute deviation from nominal abovethe upper threshold frequency or below the lower threshold frequency.The second (MF2) provides higher MPs for periods when the AC linefrequency is below the lower frequency threshold than when the AC linefrequency is above the upper threshold limit. Measured frequencies arerounded up or down.

TABLE I MP FREQUENCY MF1 MF2 60.05 Hz 3 3 60.04 Hz 2 2 60.03 Hz 1 160.02 Hz 0 0 60.00 Hz 0 0 59.98 Hz 0 0 59.97 Hz 1 2 59.96 Hz 2 4 59.95Hz 3 6

MF may be expressed as a function of x (i.e., MF=f(x)). In one exampleMF may be expressed as:

MF=|CF−NF   (2)

where:

-   CF is the measured AC line frequency in a particular sample    interval; and-   NF is the nominal AC line frequency.-   In equation (2), x is CF and NF is a constant. Note, f(x) may take    on any number of mathematical functions. Further MF may be a    function of two or more variables, for example, CF, day of the week,    time of day, and combinations thereof.

FIG. 6 is a flowchart of a method of frequency responsive loadmanagement according to an embodiment of the present invention. In step200, upper and lower threshold frequencies, the nominal AC frequency(NF) the sampling interval (SI), number of sampling intervals (N) in themoving average, scaling factor (SF), and multiplication factor (MF) areconfigured. Additionally, initial frequency and power measurements aremade to build up an initial set of data (e.g., a moving average of Nconsecutive data points) step 215 can operate on. Also in step 200, afrequency regulation credit (FRC) is set to an initial value, forexample zero. Then, in step 205, the current power consumption for afirst/next period of time equal to the sampling interval is measured asdescribed in reference to FIG. 3. The word “current” in the phrase“current power consumption” is used herein in the sense of “presenttime” not electrical flow. In step 210, for the same period of time asin step 205, the moving average power consumption of the previous Nsampling intervals is calculated as described in reference to FIG. 4. Instep 215 the difference between the power consumption measured in step205 and the moving average power consumption calculated in step 210 iscalculated (i.e., (P−M)). In step 220, a current AC frequency on the ACpower line during the same period of time as in step. 205 is measured asdescribed in reference to FIG. 3. The word “current” in the phrase“current AC frequency” is used herein in the sense of “present time” notelectrical flow.

In step 225, it is determined if the measured AC frequency is equal toor less than the lower threshold frequency. If the measured AC frequencyis equal to or lower than the lower frequency limit than the methodproceeds to step 230. In step 230, it is determined if the differencecalculated in step 215 is negative or positive. If the difference isnegative, then the method proceeds to step 235 where a credit iscalculated. If the difference is positive, then the method proceeds tostep 240 where a debit is calculated.

Returning to step 225, if the measured AC frequency is equal to orhigher than the lower frequency limit than the method proceeds to step245. In step 255, it is determined if the difference calculated in step215 is negative or positive. If the difference is positive, then themethod proceeds to step 235 where a credit is calculated. If thedifference is negative, then the method proceeds to step 240 where adebit is calculated.

After either steps 235 or 240, the method proceeds to step 250 where thefrequency regulation credit is accumulated by adding a credit from step235 or subtracting a debit from step 240 to the previous value of thefrequency regulation credit. The frequency regulation credit is storeduntil required by step 265. Optionally, the debits and credits may bestored. After step 250 the method loops back to step 205 via connectorA.

Again, returning to step 225, if the measured AC frequency is betweenthe lower and upper threshold frequencies the method proceeds to step260 where a zero credit/debit is calculated (the frequency regulationcredit will be unchanged) and the method proceeds to step 250 viasconnector B. Steps 225, 230, 235, 240, 245, and 260 can be performedsimultaneously by evaluation of equation (1) when MF can evaluate tozero when the AC frequency measured in step 220 is between the upper andlower threshold frequencies. Alternatively, if MF cannot evaluate tozero, in step 225, when the AC frequency measured in step 220 is betweenthe upper and lower threshold frequencies the method could loop directlyback to step 205.

From step 240, step 265 is periodically (as in a billing cycle)performed. In step 260, the frequency regulation credit is sent to thepower company and the frequency regulation credit reset to zero.Optionally the measurements and calculations of steps 205, 210, 215, 220235, 240 and 250 may be displayed on a readout device or computer screenor printed on a printer. Optionally the measurements and calculations ofsteps 205, 210, 215, 220 235, 240 and 250 may be stored for futureanalysis.

The amount of time to perform a loop consisting of combinations of steps205, 210, 215, 220, 225, 230, 235, 240, 245, 250 and 255 that takes thelongest to perform should be less than or equal to the samplinginterval. Steps 230 and 250 assume power consumption measured in step205 is subtracted from the moving average power consumption calculatedin step 215. If the opposite is performed, the in steps 230 and 250, thepositive and negative loops would be reversed.

FIG. 7 is block diagram of an exemplary line monitoring deviceimplemented as a power and frequency regulation meter according to anembodiment of the present invention. In FIG. 7, a power and frequencyregulation meter 300 includes a microprocessor 305, a memory unit 310, apower line interface 315, an optional display 320, an optionalinput/output interface 325 and a communication interface 330. Memoryunit 310, power line interface 315, display 320, input/output interface325 and communication interface 330 are all connected to microprocessor305. Input/output interface 324 is optionally connected to memory unit310. In use, a power from an AC power line (not shown) is connected to apower input of power line interface 315 and a load (not shown) isconnected to a power output of power line interface 315. Power lineinterface 315 supplies power for microprocessor 305, memory unit 310,display 320, input/output interface 325 and communication interface 330.Microprocessor 305 calculates customer frequency regulation debits andfrequency regulation credits as described infra with respect to FIGS. 3,4 and 5 and the method described by FIG. 6. The algorithm thatmicroprocessor performs is stored as instructions in memory unit 310.Memory unit 310 also stores data needed by and generated by themicroprocessor executing the instructions, including power consumptionmeasurements, power consumption moving averages and frequency regulationcredits. Frequency regulation credits as well as total power consumptionmay be displayed by display 320. Input/output device 325 may be used toinput the algorithm instructions and output frequency regulation creditsas well as total power consumption. Communications interface 325 may beused to receive the algorithm instructions from the power supplier andsend frequency regulation credits as well as total power consumptiondata to the power supplier.

FIG. 8 is block diagram of the power line interface of FIG. 7. In FIG.8, power line interface includes a power frequency meter 335 (similar topower frequency meter 130 of FIG. 2 and a watt-hour meter 340 similar towatt-hour meters 135A and 135B of FIG. 2. Solid-state AC frequencymeters are well known as are solid-state and electromechanical inductionAC watt meters. In an alternative embodiment, frequency meter 335 andwatt-hour meter 340 may be combined into a single solid-state device.

FIG. 9 is a mechanical drawing of an exemplary power meter according toan embodiment of the present invention. Power and frequency regulationmeter 300 may be physically packaged as illustrated in FIG. 9. In FIG. 9a case 350 includes the electronics for microprocessor 305, memory unit310, display 320, input/output interface 325 and communication interface330 of FIG. 7. On a top of case 350 is a power input fitting 355configured to connect a wire(s) from an AC power line and on a bottom ofcase 360 is a power output fitting 355 configured to connect a wire(s)to an external load at a customer residence or commercial or privateestablishment or business. In the front of case 350 is a KW-hour display365 of an internal power meter which may be mechanical or electronic, afrequency regulation display 370 which may be mechanical or electronic,a data communication socket 375, an optional power disconnect (on theoutput side) switch 380. Also on top of case 350 is a telephone/cablefitting 385 configured to connect power and frequency regulation meter300 to a telephone line or non-telephone cable communication system.Additionally an optional wireless communication device 390 may beincluded. In alternative embodiments, the physical components may belocated in other physical relationships relative to case 350 differentfrom that illustrated in FIG. 9.

While power and frequency regulation meter 300 of FIGS. 7 and 9 iswell-suited for small power users, large power users would benefit fromthe line monitoring device 115 of FIG. 1 being implemented using ageneral purpose computer where the method described herein with respectto frequency responsive load management using frequency regulationcredits described supra in FIGS. 3, 4 and 5 and the flowchart of FIG. 6with respect to steps 200, 210, 215, 225, 230, 235, 240, 345 and 250 maybe coded as a set of instructions on removable or hard media for use bythe general-purpose computer.

FIG. 10 is block diagram of an exemplary general-purpose computer. InFIG. 10, computer system 400 has at least one microprocessor or centralprocessing unit (CPU) 405. CPU 405 is interconnected via a system bus410 to a random access memory (RAM) 415, a read-only memory (ROM) 420,an input/output (I/O) adapter 425 for a connecting a removable dataand/or program storage device 430 and a mass data and/or program storagedevice 435, a user interface adapter 440 for connecting a keyboard 445and a mouse 450, a port adapter 455 for connecting a data port 460 and adisplay adapter 465 for connecting a display device 470.

ROM 420 contains the basic operating system for computer system 400. Theoperating system may alternatively reside in RAM 415 or elsewhere as isknown in the art. Examples of removable data and/or program storagedevice 430 include magnetic media such as floppy drives and tape drivesand optical media such as CD ROM drives. Examples of mass data and/orprogram storage device 435 include electronic, magnetic, optical,electromagnetic, infrared, and semiconductor devices. Examples of acomputer-readable medium include a semiconductor or solid-state memory,magnetic tape, a removable computer diskette, a random access memory(RAM), a read-only memory (ROM), a rigid magnetic disk and an opticaldisk. Current examples of optical disks include compact disk-read onlymemory (CD-ROM), compact disk-read/write (CD-R/W) and DVD. In additionto keyboard 445 and mouse 450, other user input devices such astrackballs, writing tablets, pressure pads, microphones, light pens andposition-sensing screen displays may be connected to user interface 440.Examples of display devices include cathode-ray tubes (CRT) and liquidcrystal displays (LCD).

Data from power line interface 315 of FIG. 8 in the form of watt-hourand AC line frequency measurements are supplied to the system via dataport 460. Also frequency regulation credits as well as total powerconsumption may be transmitted to the power company via devicesconnected to data port 460 and program instructions may be received fromthe power company via data port 460. Computer 400 may also be used toperform complex power/cost analysis and used to direct power consumptionreducing or power consumption increasing measures such as increasing orreducing throughputs and/or turning equipment on or off when debits arebeing generated.

A computer program with an appropriate application interface may becreated by one of skill in the art and stored on the system or a dataand/or program storage device to simplify the practicing of thisinvention. In operation, information for or the computer program createdto run the method of the present invention is loaded on the appropriateremovable data and/or program storage device 430, fed through data port460 or typed in using keyboard 445.

Thus the embodiments of the present invention prove a method, device andsystem for frequency responsive load management using frequencyregulation credits.

The description of the embodiments of the present invention is givenabove for the understanding of the present invention. It will beunderstood that the invention is not limited to the particularembodiments described herein, but is capable of various modifications,rearrangements and substitutions as will now become apparent to thoseskilled in the art without departing from the scope of the invention.Therefore, it is intended that the following claims cover all suchmodifications and changes as fall within the true spirit and scope ofthe invention.

1. A method, comprising: using an AC frequency measuring device,measuring a current AC frequency on an AC power line; using a powerconsumption measuring device, measuring a current power consumption onsaid AC power line over a period of time equal to a sampling interval;calculating a power consumption moving average of a last N power currentpower consumptions measured, where N is a positive integer greater than1; generating credits, debits or credits and debits based on saidcurrent power consumption, said current AC frequency and said powerconsumption moving average; adding said credits, debits or credits anddebits to a frequency regulation credit; and for each next samplinginterval, repeating said measuring said current AC frequency, saidmeasuring said current power consumption, said calculating said powerconsumption moving average, said generating said credits, debits orcredits and debits, and said adding said credits, debits or credits anddebits to said frequency regulation credit.
 2. The method of claim 1,wherein a credit is generated when said current power consumption whencompared to said power consumption moving average is driving said ACpower line toward a nominal AC frequency of said AC power line.
 3. Themethod of claim 1, wherein a debit is generated when said current powerconsumption when compared to said power consumption moving average isdriving said AC power line away from a nominal AC frequency of said ACpower line.
 4. The method of claim 1, wherein when said currentfrequency is between an upper threshold frequency and a lower thresholdfrequency no credits or debits are generated.
 5. The method of claim 4,wherein said upper threshold frequency is greater than a nominal ACfrequency of said AC power line and said lower threshold frequency isless than said nominal AC frequency.
 6. The method of claim 1, furtherincluding: initializing a power consumption moving average of Nconsecutive power consumption measurements, each power consumptionmeasurement made over a respective period of time equal to said samplinginterval.
 7. The method of claim 1, further including, periodicallytransferring said frequency regulation credit to a power companysupplying AC power on said AC power line.
 8. The method of claim 1,wherein said generating said credit or debit includes: generating adebit when said current AC frequency is greater than or equal to anupper threshold frequency and said current power consumption is lessthan said power consumption moving average; generating a credit whensaid current AC frequency is greater than or equal to an upper thresholdfrequency and said current power consumption is greater than said powerconsumption moving average; generating a debit when said current ACfrequency is less than or equal to a lower threshold frequency and saidcurrent power consumption is greater than said power consumption movingaverage; generating a credit when said current AC frequency is less thanor equal to a lower threshold frequency and said current powerconsumption is less than said power consumption moving average; and notgenerating a credit or a debit when said current AC frequency is betweensaid upper threshold frequency and said lower threshold frequency.
 9. Adevice, comprising: an AC frequency measuring device; one or more ACpower measuring devices; means for generating a frequency regulationcredit based on signals from said AC frequency measuring device and saidAC power measuring device, said means for generating said frequencyregulation credit connected to said AC frequency measuring device and tosaid AC power measuring device; and means for displaying, recording orboth displaying and recording said frequency regulation credit.
 10. Thedevice of claim 9, further including: means to display, record or bothdisplay and record power consumption measured by said one or more ACpower measuring devices.
 11. The device of claim 9, wherein said meansfor generating said frequency regulation credit includes, amicroprocessor and a memory unit connected to said microprocessor. 12.The device of claim 11, further including: a communications interfaceconnected to said microprocessor, an input/output device connected tosaid microprocessor or both said communications interface connected tosaid microprocessor and said input/output device connected to saidmicroprocessor .
 13. The device of claim 11, further including one ormore of: a telephone modem connected to said microprocessor, a cablemodem connected to said microprocessor and a wireless modem connected tosaid microprocessor.
 14. The device of claim 11, further including adata communication socket connected to said microprocessor, said memoryunit or both said microprocessor and said memory unit.
 15. The device ofclaim 9, further including means to connect said AC frequency measuringdevice to an AC power line and means to connect said one or more ACpower measuring devices between said AC power line and an external load.16. The device of claim 15, wherein: said frequency regulation credit isincreased when said current power consumption is driving said AC powerline toward a nominal AC frequency of said AC power line; said frequencyregulation credit is decreased when said current power consumption isdriving said AC power line away from said nominal AC frequency; and saidfrequency regulation credit is unchanged when an AC frequency of said ACpower line is between an upper threshold frequency and a lower thresholdfrequency.
 17. The device of claim 9, wherein said means for generatinga frequency regulation credit and said means for displaying, recordingor both displaying and recording said frequency regulation credit iscomprised of a general-purpose computer.
 18. A computer systemcomprising a processor, an address/data bus coupled to said processor,and a computer-readable memory unit coupled to communicate with saidprocessor, said memory unit containing instructions that when executedby the processor implement a method for frequency responsive loadmanagement using frequency regulation credits, said method comprisingthe computer implemented steps of: receiving from an AC frequencymeasuring device, a current AC frequency on an AC power line; receivingfrom a power consumption measuring device, a current power consumptionon said AC power line over a period of time equal to a samplinginterval; calculating a power consumption moving average of a last Npower current power consumptions measured, where N is a positive integergreater than 1; generating credits, debits or credits and debits basedon said current power consumption, said current AC frequency and saidpower consumption moving average; adding said credits, debits or creditsand debits to a frequency regulation credit, storing said frequencyregulation credit on said memory unit; and for each next samplinginterval repeating said steps of receiving from said AC frequencymeasuring device said current AC frequency on an AC power line,receiving from said power consumption measuring device said currentpower consumption, calculating said power consumption moving average,generating said credits, debits or credits and debits, adding saidcredits, debits or credits and debits to said frequency regulationcredit, and storing said frequency regulation credit on said memoryunit.
 19. The computer system of claim 18, wherein a credit is generatedwhen said current power consumption when compared to said powerconsumption moving average is driving said AC power line toward anominal AC frequency of said AC power line.
 20. The computer system ofclaim 18, wherein a debit is generated when said current powerconsumption when compared to said power consumption moving average isdriving said AC power line away from a nominal AC frequency of said ACpower line.
 21. The computer system of claim 18, wherein when saidcurrent frequency is between an upper threshold frequency and a lowerthreshold frequency no credits or debits are generated.
 22. The computersystem of claim 21, wherein said upper threshold frequency is greaterthan a nominal AC frequency of said AC power line and said lowerthreshold frequency is less than said nominal AC frequency.
 23. Thecomputer system of claim 18, the method further including: initializinga power consumption moving average of N consecutive power consumptionmeasurements, each power consumption measurement made over a respectiveperiod of time equal to said sampling interval.
 24. The computer systemof claim 18, the method further including, periodically transferringsaid frequency regulation credit to a power company supplying AC poweron said AC power line.
 25. The computer system of claim 18, wherein saidmethod step of generating a credit or debit includes: generating a debitwhen said current AC frequency is greater than or equal to an upperthreshold frequency and said current power consumption is less than saidpower consumption moving average; generating a credit when said currentAC frequency is greater than or equal to an upper threshold frequencyand said current power consumption is greater than said powerconsumption moving average; generating a debit when said current ACfrequency is less than or equal to a lower threshold frequency and saidcurrent power consumption is greater than said power consumption movingaverage; generating a credit when said current AC frequency is less thanor equal to a lower threshold frequency and said current powerconsumption is less than said power consumption moving average; and notgenerating a credit or a debit when said current AC frequency is betweensaid upper threshold frequency and said lower threshold frequency. 26.The method of claim 1, wherein said frequency regulation credit iscalculated using the formula:FRC=SF Σ[(P−M)(MF)] where: FRC is the frequency regulation credit; P isthe power consumed in a sampling interval; M is the moving average ofpower consumed over N sampling intervals where N is a whole positiveinteger equal to or greater than 2 (the power consumption movingaverage); MF is a multiplier function; and SF is an optional scalingfactor so the FRC is not an unreasonably large or small number in termsof output or display.
 27. The device of claim 9, wherein said frequencyregulation credit is calculated using the formula:FRC=SF Σ[(P−M)(MF)] where: FRC is the frequency regulation credit; P isthe power consumed in a sampling interval; M is the moving average ofpower consumed over N sampling intervals where N is a whole positiveinteger equal to or greater than 2 (the power consumption movingaverage); MF is a multiplier function; and SF is an optional scalingfactor so the FRC is not an unreasonably large or small number in termsof output or display.
 28. The computer system of claim 18, wherein saidfrequency regulation credit is calculated using the formula:FRC=SF Σ[(P−M)(MF)] where: FRC is the frequency regulation credit; P isthe power consumed in a sampling interval; M is the moving average ofpower consumed over N sampling intervals where N is a whole positiveinteger equal to or greater than 2 (the power consumption movingaverage); MF is a multiplier function; and SF is an optional scalingfactor so the FRC is not an unreasonably large or small number in termsof output or display.